Details

Autor(en) / Beteiligte

• Busch, D
• Lucker, T
• Wosniok, W

Titel

Effects of Changing Salt Concentrations and Other Physical-chemical Parameters on Bioavailability and Bioaccumulation of Heavy Metals in Exposed Dreissena polymorpha (PALLAS, 1771)

Ist Teil von

• Limnologica, 1998, Vol.28 (3), p.263-274

Erscheinungsjahr

1998

Beschreibungen/Notizen

• By use of the bivalve Dreissena polymorpha, a biological monitoring of pollutants in the River Weser has been carried out from 1988 to 1993. Mussels originating from a low-level polluted lake were exposed at 15 water control stations in the saltpolluted Weser for 12 weeks. The suitability of Dreissena for the active biomonitoring of pollutants in extremely polluted rivers has been confirmed. A high tolerance for adverse environmental conditions is one of the preconditions for the use of an organism for active accumulation biomonitoring. The concentrations of Pb, Cd, Cr, Ni, Zn and Cu in soft tissues of Dreissena, reached over space and time, mirror the differences in the bioavailability of metals at the sampling stations. Mathematical analysis shows a significant influence of salinity, DOC and seasonal effects on bioavailability of heavy metals. The mathematical model explains a substantial part of the occurring variances in bioaccumulation of heavy metals in soft tissues of Dreissena polymorpha in both analysed periods (Period 1988-1990: Cr: 83.8%; Ni: 65.6%; Zn: 54.2%; Pb: 38.6%; Cu: 33.0%; Cd: 32.2%; Period 1991-1993: Zn: 58.8%; Cd: 58.1%; Pb: 56.3%; Cr: 54.7%; Ni: 45.4%; Cu: 41.7%). During 1988-1990 in the River Weser, the heavy metal concentrations in water played only a subordinate role in bioaccumulation. Small effects have been ascertained for chromium (5%), zinc (9%) and cadmium (10.5% expl. variance, modelling on zinc concentrations) and somewhat larger for copper (19%). During 1991-1993, salt pollution decreased and the effects of salinity on bioaccumulation of heavy metals were remarkably reduced. For chromium no further effect of salinity was detectable. The effects were reduced for cadmium (from 21.6% to 12.0% expl. variance) and for lead (from 20.4% to 14.3% expl. variance). Only for the essential zinc the moderate influence (9.3% expl. variance) remained at the former level. The uptake of nickel and copper was unaffected by salinity. During 1991-1993, the role of heavy metal concentrations in unfiltered water changed. For lead, it became a dominant influence, 42% of the explained variances of lead concentrations in Dreissena could be explained by concentrations in unfiltered water. The effects on copper accumulation increased from 18.7% to 32.4%.